Polarized relay



April 5, 1932.

F. c. LARSON 1,852,210

POLAR I ZED RELAY 2 Sheets-Sheet 1 Filed Feb. 13. 1928 gnventoz April 5, 1932. F. c. LARSON 1,852,210

POLARIZED RELAY Filed Feb. 13. 1928 2 Sheets-Sheet 2 j kdewzicf Zan5'072/ Patented Apr. 5, 1932 UNITE STATES PATENT GFFICE FREDERICK C. LARSON, OF ST. PAUL, MINNESOTA, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW' YORK POLARIZED RELAY 'This invention relates to improvements in polarized relays, particularly, although not exclusively, adapted for railway signal use.

It is the present practice in block signal systems on railways to provide signals of three kinds, namely, a permissive signal or green light, a warning signal or yellow light and prohibitory signal or redlight. These signals are under control of a polarized relay having a neutral armature which is arranged to automaticaly render the prohibitory signal operative when neither of the other signals are displayed or when any part of the system becomes defective. The operating circuit for the polarized relay is controlled by the passage of the trains so' that electric current fiowsthrough the coils of the relay in one direction to give a permissive or green signal and in the reverse direction to display a warning or yellow signal. In the absence of means for preventing it, the neutral armature operates to displaythe prohibitory signal in the brief interval while the current is being reversed in the relay coils. Thus in the normal operation of such relays an undesirable signal is displayed momentarily between the showing of two other signals such as between the permissive or green signal and the warning or yellow signal. This, in the past, has led to confusion nd mistakes on the part of the train operators. To overcome this defect slow acting relays in auxiliary circuits have been employed but such means are expensive and otherwise not entirely satisfactory.

It is the object of this invention to provide simplified means for controlling the neutral armature of a polarized relay during reversals of current in the operating coils. More particularly it is my object to prevent the displaying of undesirable signals between desired signals by simple, efficient and safe means for controlling the neutral armatures of polarized relays in block signal systems.

The invention will be best understood by reference to the accompanying drawings in which Figure 1 is a bottom plan view of the invention applied to a polarized relay of one of the types used in railway signal systems, a part of the neutral armature being broken away to show the polarized armature; Fig. 2 is a front elevation of the invention; Fig. 3 is a section taken on the line 33 of Fig. 2, with the main or control coils in side View; l is a longitudinal section taken on the line t of Fig. 3 and Fig. 5 is diagram of the relay in a simplified circuit and indicat ing its operation.

As shown in the drawings my device is attac ied to a polarized relay having a supporting base 7. A bed 8 of insulating material is secured in parallel spaced relation to the base 7. Upon the top of the bed 8 is supported a pair of operating coils 9 having suitable terminals 10 for connection with line circuit wires 11. As shown in Fig. 5 the coils 9 have primary windings 12, in series in the circuit including the wires 11, and secondary windings 13 in an auxiliary circuit 14:. This circuit 14 also includes coils 15 wound upon cores 16 of an electroinagnet adapted to hold the neutral armature 17 of the instrument in predetermined or energized position when cufrent reversals occur in the circuit including the primary coils 12. The details of construction of this armature are more fully described hereinafter.

Cores 18 and 19 of the coils 9 project adjacent to the armature 1'? so as to attract the same when energized by current flowing through these coils. another armature 20 is operatively connected withthearmature 17 by means of a lever 21 0t non-magnetic materialand this armature 20 is arranged to be attracted by magnetism of the cores 16 when energized. The armatures 17 and 20 are rigidly connected together and have a common pivot 22.

A polarized armature 28 is arranged to be operated by the magnetic effect of current flowing in the coils 12 in a manner well known in this art. Thus the armature 23 has per manent magnets 24; and 25 projecting adjacent to the cores 18 and 19 respectively. These magnets are so arranged that when current flows through the coils 12 in one direction the polarity relative to the cores 18 and 19 causes the armature 23 to be moved to one position and reversal of current through the coils 12 causes movement of the armature 23 to another position.

In Fig. 5, the polar armature 23 is shown as mounted on a horizontal axis, for the purpose of clearly illustrating the principle of the invention, this armature 23, in one of the actual embodiments of the invention, as illustrated in Fig. 4, being mounted on a vertical axis 42, all as described fully below.

Simplified circuits are shown in Fig. for controlling signals 26, 27 and 28 representing respectively a green light or permissive signal, a yellow light or warning signal and a red light or prohibitive signal. The circuits for operating these signals are supplied with current from a battery 29 having a circuit wire 30 connecting the same to the armature 17. Another circuit wire 31 has branches 32, 33 and 34 including the signals 26, 27 and 28 respectively. A wire 35 electrically connects the polarized armature 23 with a contact 36 for the armature 17. The branch circuit 34 has a contact 37 for the armature 17, located opposite the contact 36. Contacts 38 and 39 in the branch circuits 32 and 33 respectively are severally arranged to complete the circuit with the wire 35 through the polarized armature 23. A pole changer 40 is arranged in the circuit with the wires 11 and with a control circuit 41 supplying direct current to the operating coils 12. I

The structure described above with reference to the diagrammatic illustration in Fig. 5 is shown more in detail in Figs. 1 to 4, inelusive. The ends of the cores 18 and 19 project downward as shown in Figs. 3 and 4 adjacent to the armature 17 while the pivot 22 for this neutral armature is mounted in bearings 2205 upon a horizontal axis. A pivot 42 for the polarized armature 23 is arranged upon a vertical axis between the lower ends of the cores 18 and 19. Disposed between the permanent magnets 24 and 25 is a bar 43 of non-magnetic material which is fixed to both of said magnets, the magnets being of the common U shape, each stranding the adjacent core of the operating coils 9 as clearly shown in Fig. 4. At each end the magnet 23 is provided with projections 44 carrying insulated conductors 45. Pairs of spring fingers 46 and 47 are movable by the armature 23 to engage the contacts 38 and 39 respectively. Both of the bars may be connected to the wire 35 and to further insure positive operation a pair of contacts 39 are provided in the circuit 33 and another pair 38 for the circuit 32.

The neutral armature 17 has a pair of arms 48 rigidly secured thereto and upon the ends of these arms 48 are spring fingers 49 for engaging the contacts 36. The arms 48 also carry spring contact fingers 50 for engaging the contacts 37 when the armature 17 is in deenergized or dropped position. As shown in Figs. 1 and 3, the lever 21 is also rigidly connected to the armature 17 and projects forward therefrom. Upon its forward or free end the lever 21 has fixed thereto the armature 20 for the electro-magnet consisting of the coils 15 and cores 16. The cores 16 are preferably threaded in the bed 8 as shown in Fig. 3 and project beneath the same adjacent to the armature 20. To maintain a safe air gap between the face of each core 16 and the armature 20 I provide a series of small phospher-bronze pins 51 which project a few thousandths of an inch from the face of the cores.

Suitable binding posts 10a are provided for the wires 14 to facilitate connecting the coil 15 in circuit with the secondary winding 13 of the coils 9. Projecting upward through the bed 8 and fixed therein is a series of binding posts. These binding posts are respectively, 52 for the circuit wire 34, 53 for the wire 35, 54 for the wire 32 and 55 for the wire 33. The bed 8 is held in spaced parallelrelation to the base 7 by a series of side panels 56, preferably of glass, and a series ofbolts 57 are disposed at the four corners of the instrument, extending through the perforations 58 (Fig. 1) inthe bed 8.

It will be understood that the pole changer 40 for the current supply wires 41 represents diagrammatically any mechanism for changing the polarity. In railway block signal systems, the change in polarity is efi'ected through circuits connected to the track and the polarity is changed or the circuit 41 broken upon the passage of the trains from one block to another.

Operation In operation current is allowed to flow from the track or control circuit 41 through the coils 12 when either the permissive signal 26 or warning signal 27 is to be displayed. When a permissive signal isto be displayed polarity Of'COIltI'Ol circuit wires 11 is as indicated in Fig. 5. Thus the magnetized cores 18 and 19 cause the permanent magnets 24 and 25 to move the armature 23 to a position such that the circuit between the wires 35-and 32 is closed at the contact 38. This causes the spring fingers 46 to engage the contacts38, the wire 35 being in electrical connection with the bar 45. As will be readily understood this completes the circuit from the battery 29 through the wires 31, 32, signal 26, contact 38, bar 45 on armature 23, wire 35, contact 36,

armature 17 and wire 30.

When in the operation of the system the polarity of the wires 11 is changed so as to reverse the current therethrough, a brief interval of time is required for the change in polarity of the cores 18 and 19. During this interval, in the absence of my device, the armature 17 would drop by gravityand complete the circuit through the prohibitive signal 28 by completing the branch circuit 34 at iii) the contact 37. However, I prevent this dropping of the armature 17 by my arrangement of the electro-magnet having the coils 15 in circuit with the secondary windings 13 of the operating coils 9. The rapidly dropping voltage and subsequent building up in the reverse direction causes an induced current to be set up in the coils 13 and circuit wires 14 which energizes the coils 15 and magnetizes the cores 16 so that the armature 20 is attracted and held in its normal position adjacent to the cores 16. This through the lever 21 retains the armature 17 in its stationary or energized position for the brief interval of time necessary to reverse the polarity of the control circuit and magnetism of the cores 18 and 19.

Upon the changing of the polarity of the control circuit the coils 12 operate to change the polarity of the cores 18 and 19. This causes a corresponding change in the position of the polar armature 23 which in turn results in closing of the spring fingers 47 against the contacts 39. Now the branch circuit .33 is complete through the warning signal 27. Obviously when the circuit 11 is broken the operating coils 9 arede-energized. This allows the armature 17 to drop and complete the circuit through the prohibitive signal 28, through the armature 17, spring fingers 50 and contacts 37.

It will be noted that the axes of the cores 18 and 19 are located a short distance from the pivot 22-01 the armature 17 whereas the axes of the cores 16 are located at a much greater distance from the pivot 22. Thus the electro-magnet consisting of the coils 15 and cores 16 has a mechanical advantage over the operating coils 12 with their cores 18 and 19. This is necessary in the arrangement shown in order to compensate for the relatively small current which is induced in the secondary windings 13 as compared to that flowing in the coils 12. I have found that by locating the armature 20 at such a point that it has about four times the leverage of the armature 17, the effect of the induced current set up in the secondary winding 13 is suificient to retain the neutral armature in stationary or energized position during the interval of time required for the reversal of the current in the operating coils 12.

Having described myinvention what I claim is new and desire to protect by Letters Patent is:

1. In a polarized relay having operating coils and a neutral armature, a signal circuit under control of said neutral armature, an inductive circuit including windings of said coils, electromagnetic means in said inductive circuit adapted to be operated by induced current from said winding of the operating coils and means operable by said electromagnetic means and connected to said armature whereby said signal circuit is rendered inoperative during' reversals of current in said operating coils.

2. In a polarized relay having operating coils in circuit with means for reversing the current therethrough, the combination with a neutral armature arranged to be retained in predetermined position by the magnetic eiiect of current in said coils, and electromagnetic means operable by induced current upon the reversal of current in said coils to retain said armature in said predetermined position during the reversal of current.

3. The combination with a polarized relay having operating coils and a neutral arma ture adapted to be energized thereby, said coils having primary and secondary windings, means for reversing the current in said primary windings, an auxiliary circuit including said secondary winding and electromagnetic means in said auxiliary circuit, operable by induced current therein to retain said armature in energized position during reversals of current in said primary windmgs.

4. The combination in a polarized relay of an operating coil having primary and secondary windings, means for reversing the current in said primary winding, a neutral armature adapted to be moved to energized position by the magnetic effect of said coil, electromagnetic means arranged to retain said, armature in energized position during momentary current changes in said primary winding and means operable by induced current created in said secondary winding to energize said electromagnetic means.

5. The combination with an electromagnet having a coil and means for effecting current changes in said coil, of neutral and polar armatures under control of said magnet, means associated with said magnet for establishin g an induced current by current changes in the coil of said magnet and magnetic means for utilizing said induced current to retain said neutral armature stationary during current changes in said coil.

6. The combination of a relay having neutral and polar armatures, an operating coil for said armatures, a circuit including said coil, polarity changing means in said circuit, said neutral armature being movable to one position when current is flowing in said coil and to another position upon the interruption of said circuit and means separate from said cicuit for retaining said neutral armature in said first mentioned position when said circuit is momentarily interrupted by currem reversals therein.

7. The combination of a relay having neutral and polar armatures, and operating coil for said armatures having primary and secondary windings, a control circuit includ ing said primary windings, a secondary circuit including said secondary windings, po-

larity changing means in said control circuit,

said neutral armature being movable to one position when current is flowing in said primary windings and to another position upon the interruption of said. control circuit, a lever arm connected to said neutral armature, another armatureconnected to said arm and an electromagnet associated with said last mentioned armature and having coils in secondary circuit whereby said neutral armature is retained in said first mentioned position when said control circuit is momentarily interrupted by current reversals therein.

8.. The combination with a railway signal system having permissive, warning and prohibitory signals, branch circuits severally including said signals, a control circuit, means for changingthe polarity of said control circuit,,of a polarized relay having coils in said control circuit and having polar and neutral armatures controlling said branch circuits, said neutral armature beingnormallyretained in energized position and said branch cireuit,.including said prohibitory signal, being under control of said neutral armature and arranged to render said prohibitory signal operative when said armature is de-energized and means separate from said control circuit for retaining said neutral armature in energized .position during momentary changes in the current in said control, circuit.

9. In a relay,in combination, a neutral armature, an operating winding for attracting said armature when energized, a holding winding for the neutral armature, which holding win ding is separate from,,and non-inductively positioned relatively to, the operating winding, and energizing means for the holding winding inductively energized on change in current flow in the operating winding for holding the armature in attracted position for a time after de-energization of the operating winding.

10. In av relay, in combination.. a neutral armature, an operating winding for attracting said armature when energized, and a holding winding for the neutral armature, inductively coupled with the operating winding, for holding the armature in attracted position for a time after de-energization of the operating winding. said holding win din g being'positioned to have a distinct mechanical advantage over the operating winding in acting on the armature.

11.. In a relay, in combination, a pivoted neutral armature, an operating core having operating coils thereon for attracting the armature when energized, a holding core positioned to attract and hold the armature when energized, and a winding'on the holding core connected in series with aninsulated winding on the operating core, whereby to inductively hold up the armature upon de-energization ot the operating coils.

12. In a relay, in combination, a neutral i armature, an operating winding for attracting said armature when energized, energizing means for the operating winding, and a hold ing winding, for the neutral armature non-inductively positioned with relation to the op erating winding, and arranged to have its energization dependent upon an inductive effect from the energizing means for the operating winding, for holding the armature in attracted position for a time after de-energization of the operating winding.

i3. In a relay, in combination, a neutral armature, an operating winding for attracting said armature when energized, energizing means for the operating winding, and a holding winding for the neutral armature arranged to have its energization dependent upon an inductive effect from the energizing means for the operating winding, for holding the armature in attracted position for a time after de-energization of the operating winding, said holding winding being positioned to have a distinct mechanical advantage over the operated winding in acting on the armature.

14. In a relay, in combination, a pivoted neutral armature, an operating core having operating coils thereon for attracting the armature when energized, energizing means for the operating coils, a holding core positioned to attract and hold the armature when energized, and a winding on the holding core energized from said energizing means for the operating coil, whereby to hold up the armature upon de-energization of the operating coils.

15. In a relay, in combination, a pivoted neutral armature, an operating core having operating coils thereon for attracting the armature when energized, energizing means for the operating coils, a holding core positioned to attract and hold the armature when energized, and a winding on the holding core energized from said energizing means for the operating coil, whereby to inductively hold up the armature upon de-energization of the operating coils.

16. In combination, a main electromagnet having an operating winding, a main tractive armature controlled thereby, an auxiliary winding in inductive relation to said operating winding, an auxiliary electromagnet having'its winding connected with said auxiliary winding, and an auxiliary armature controlled by said auxiliary electromagnet and connected with said main armature to hold the latter closed while the auxiliary electromagnet is energized, whereby said main armature does not open when the polarity of the current supplied to said operating winding is reversed.

17 In combination, an electromagnet having the usual operating winding, a tractive armature controlled thereby, an auxiliary electromagnetic device for keeping said armature in the closed position, and an auxiliary winding in inductive relation to said operating winding for momentarily supplying current to said auxiliary device when the polarity of the current in said operating winding is reversed.

18. In combination, an electromagnet having the usual operating winding, a tractive armature controlled thereby, an auxiliary winding in inductive relation to said operating winding, and means controlled by the current induced in said auxiliary winding when the polarity of the current in said operating winding is reversed for preventing said armature from opening.

19. In a relay, a main armature, a retaining armature, an elongated member of nonmagnetic material connecting the two armatures in spaced relationship, an operating winding for the main armature and a retaining winding having its energization dependent upon the operating winding and positioned to operate on the retaining armature.

In testimony whereof, I have hereunto signed my name to this specification.

FREDERICK C. LARSON. 

